Check the validity of the URL before letting someone save it.
Corinna found that the morpho hangs if the metacat url is set incorrectly. But I can't reproduce it. If the url missed a "metacat" ( see using https://poseidon.limnology.wisc.edu/metacat rather than https://poseidon.limnology.wisc.edu/metacat/metacat), morpho is still responsive. But the login takes for ever.
No matter what behavior it is, we need to check the the validity of the URL.